Yes, Skyhawk was only in Santa Clara. It was post-Marriott, i.e KECO. Other KECO parks had this ride, too, such as Kings Island and Kings Dominion. In southern California, Knott's Berry Farm (not a KECO park) had one, too.

If you notice in the picture above, there are no canopies. In the original design, there were clear canopies that covered the cabins.

Skyhawk was placed just to the left of First Aid/School House building in Hometown Square.

And yes, Skyhawk opened for the 1989 season. I remember they were being tested while I was in training in February and March of 1989. During breaks some of the trainees rode it so they could test it on real people. Those darn canopies kept falling off, even back then.

That was a really strange ride. It wasn't terribly good, either. I recall that when you pushed the little control stick to roll the car over the car would jerk to the left/right and whirr upside down, and if you let go it'd jerk in the other direction and return to a level position. A novel idea, but badly executed.